/*
 * @(#)JnlpDownloadServlet.java 1.10 07/03/15 Copyright (c) 2006 Sun
 * Microsystems, Inc. All Rights Reserved. Redistribution and use in source and
 * binary forms, with or without modification, are permitted provided that the
 * following conditions are met: -Redistribution of source code must retain the
 * above copyright notice, this list of conditions and the following disclaimer.
 * -Redistribution in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution. Neither the name of
 * Sun Microsystems, Inc. or the names of contributors may be used to endorse or
 * promote products derived from this software without specific prior written
 * permission. This software is provided "AS IS," without a warranty of any
 * kind. ALL EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES,
 * INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
 * PURPOSE OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN MIDROSYSTEMS, INC.
 * ("SUN") AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY
 * LICENSEE AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
 * DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR ANY LOST
 * REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL,
 * INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY
 * OF LIABILITY, ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE,
 * EVEN IF SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. You
 * acknowledge that this software is not designed, licensed or intended for use
 * in the design, construction, operation or maintenance of any nuclear
 * facility.
 */

package jnlp.sample.servlet;

import java.io.IOException;
import java.util.Date;
import java.util.ResourceBundle;

import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * This Servlet class is an implementation of JNLP Specification's Download
 * Protocols. All requests to this servlet is in the form of HTTP GET commands.
 * The parameters that are needed are:
 * <ul>
 * <li><code>arch</code>,
 * <li><code>os</code>,
 * <li><code>locale</code>,
 * <li><code>version-id</code> or <code>platform-version-id</code>,
 * <li><code>current-version-id</code>,
 * <li>code>known-platforms</code>
 * </ul>
 * <p>
 * 
 * @version 1.8 01/23/03
 */
public class JnlpDownloadServlet extends HttpServlet
{

    /**
     * 
     */
    private static final long serialVersionUID = -351516869579920417L;

    // Localization
    private static ResourceBundle _resourceBundle = null;

    // Servlet configuration
    private static final String PARAM_JNLP_EXTENSION = "jnlp-extension";

    private static final String PARAM_JAR_EXTENSION = "jar-extension";

    // Servlet configuration
    private Logger _log = null;

    private JnlpFileHandler _jnlpFileHandler = null;

    private JarDiffHandler _jarDiffHandler = null;

    private ResourceCatalog _resourceCatalog = null;

    /** Initialize servlet */
    public void init(ServletConfig config) throws ServletException
    {
	super.init(config);

	// Setup logging
	_log = new Logger(config, getResourceBundle());
	_log.addDebug("Initializing");

	// Get extension from Servlet configuration, or use default
	JnlpResource.setDefaultExtensions(config.getInitParameter(PARAM_JNLP_EXTENSION), config
		.getInitParameter(PARAM_JAR_EXTENSION));

	_jnlpFileHandler = new JnlpFileHandler(config.getServletContext(), _log);
	_jarDiffHandler = new JarDiffHandler(config.getServletContext(), _log);
	_resourceCatalog = new ResourceCatalog(config.getServletContext(), _log);
    }

    public static synchronized ResourceBundle getResourceBundle()
    {
	if (_resourceBundle == null)
	{
	    _resourceBundle = ResourceBundle.getBundle("jnlp/sample/servlet/resources/strings");
	}
	return _resourceBundle;
    }

    public void doHead(HttpServletRequest request, HttpServletResponse response)
	    throws ServletException, IOException
    {
	handleRequest(request, response, true);
    }

    /**
     * We handle get requests too - eventhough the spec. only requeres POST
     * requests
     */
    public void doGet(HttpServletRequest request, HttpServletResponse response)
	    throws ServletException, IOException
    {
	handleRequest(request, response, false);
    }

    private void handleRequest(HttpServletRequest request, HttpServletResponse response,
	    boolean isHead) throws IOException
    {
	String requestStr = request.getRequestURI();
	if (request.getQueryString() != null)
	    requestStr += "?" + request.getQueryString().trim();

	// Parse HTTP request
	DownloadRequest dreq = new DownloadRequest(getServletContext(), request);
	if (_log.isInformationalLevel())
	{
	    _log.addInformational("servlet.log.info.request", requestStr);
	    _log.addInformational("servlet.log.info.useragent", request.getHeader("User-Agent"));
	}
	if (_log.isDebugLevel())
	{
	    _log.addDebug(dreq.toString());
	}

	long ifModifiedSince = request.getDateHeader("If-Modified-Since");
	_log.addDebug("If-Modified-Since:" + new Date(ifModifiedSince));
	// Check if it is a valid request
	try
	{
	    // Check if the request is valid
	    validateRequest(dreq);

	    // Decide what resource to return
	    JnlpResource jnlpres = locateResource(dreq);
	    _log.addDebug("JnlpResource: " + jnlpres);

	    if (_log.isInformationalLevel())
	    {
		_log.addInformational("servlet.log.info.goodrequest", jnlpres.getPath());
	    }

	    DownloadResponse dres = null;

	    if (isHead)
	    {

		int cl = jnlpres.getResource().openConnection().getContentLength();

		// head request response
		dres = DownloadResponse.getHeadRequestResponse(jnlpres.getMimeType(), jnlpres
			.getVersionId(), jnlpres.getLastModified(), cl);

	    }
	    else if (ifModifiedSince != -1
		    && (ifModifiedSince / 1000) >= (jnlpres.getLastModified() / 1000))
	    {
		// We divide the value returned by getLastModified here by 1000
		// because if protocol is HTTP, last 3 digits will always be
		// zero. However, if protocol is JNDI, that's not the case.
		// so we divide the value by 1000 to remove the last 3 digits
		// before comparison

		// return 304 not modified if possible
		_log.addDebug("return 304 Not modified");
		dres = DownloadResponse.getNotModifiedResponse();

	    }
	    else
	    {

		// Return selected resource
		dres = constructResponse(jnlpres, dreq);
	    }

	    dres.sendRespond(response);

	}
	catch (ErrorResponseException ere)
	{
	    if (_log.isInformationalLevel())
	    {
		_log.addInformational("servlet.log.info.badrequest", requestStr);
	    }
	    if (_log.isDebugLevel())
	    {
		_log.addDebug("Response: " + ere.toString());
	    }
	    // Return response from exception
	    ere.getDownloadResponse().sendRespond(response);
	}
	catch (Throwable e)
	{
	    _log.addFatal("servlet.log.fatal.internalerror", e);
	    response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
	}
    }

    /**
     * Make sure that it is a valid request. This is also the place to implement
     * the reverse IP lookup
     */
    private void validateRequest(DownloadRequest dreq) throws ErrorResponseException
    {
	String path = dreq.getPath();
	if (path.endsWith(ResourceCatalog.VERSION_XML_FILENAME) || path.indexOf("__") != -1)
	{
	    throw new ErrorResponseException(DownloadResponse.getNoContentResponse());
	}
    }

    /**
     * Interprets the download request and convert it into a resource that is
     * part of the Web Archive.
     */
    private JnlpResource locateResource(DownloadRequest dreq) throws IOException,
	    ErrorResponseException
    {
	if (dreq.getVersion() == null)
	{
	    return handleBasicDownload(dreq);
	}
	else
	{
	    return handleVersionRequest(dreq);
	}
    }

    private JnlpResource handleBasicDownload(DownloadRequest dreq) throws ErrorResponseException,
	    IOException
    {
	_log.addDebug("Basic Protocol lookup");
	// Do not return directory names for basic protocol
	if (dreq.getPath() == null || dreq.getPath().endsWith("/"))
	{
	    throw new ErrorResponseException(DownloadResponse.getNoContentResponse());
	}
	// Lookup resource
	JnlpResource jnlpres = new JnlpResource(getServletContext(), dreq.getPath());
	if (!jnlpres.exists())
	{
	    throw new ErrorResponseException(DownloadResponse.getNoContentResponse());
	}
	return jnlpres;
    }

    private JnlpResource handleVersionRequest(DownloadRequest dreq) throws IOException,
	    ErrorResponseException
    {
	_log.addDebug("Version-based/Extension based lookup");
	return _resourceCatalog.lookupResource(dreq);
    }

    /**
     * Given a DownloadPath and a DownloadRequest, it constructs the data stream
     * to return to the requester
     */
    private DownloadResponse constructResponse(JnlpResource jnlpres, DownloadRequest dreq)
	    throws IOException
    {
	if (jnlpres.isJnlpFile())
	{
	    // It is a JNLP file. It need to be macro-expanded, so it is handled
	    // differently
	    boolean supportQuery = JarDiffHandler.isJavawsVersion(dreq, "1.5+");
	    _log.addDebug("SupportQuery in Href: " + supportQuery);

	    // only support query string in href for 1.5 and above
	    if (supportQuery)
	    {
		return _jnlpFileHandler.getJnlpFileEx(jnlpres, dreq);
	    }
	    else
	    {
		return _jnlpFileHandler.getJnlpFile(jnlpres, dreq);
	    }
	}

	// Check if a JARDiff can be returned
	if (dreq.getCurrentVersionId() != null && jnlpres.isJarFile())
	{
	    DownloadResponse response = _jarDiffHandler.getJarDiffEntry(_resourceCatalog, dreq,
		    jnlpres);
	    if (response != null)
	    {
		_log.addInformational("servlet.log.info.jardiff.response");
		return response;
	    }
	}

	// check and see if we can use pack resource
	JnlpResource jr = new JnlpResource(getServletContext(), jnlpres.getName(), jnlpres
		.getVersionId(), jnlpres.getOSList(), jnlpres.getArchList(), jnlpres
		.getLocaleList(), jnlpres.getPath(), jnlpres.getReturnVersionId(), dreq
		.getEncoding());

	_log.addDebug("Real resource returned: " + jr);

	// Return WAR file resource
	return DownloadResponse.getFileDownloadResponse(jr.getResource(), jr.getMimeType(), jr
		.getLastModified(), jr.getReturnVersionId());
    }
}
